Development of a New Marine Exposure Site on the Atlantic North-west Coast of Ireland

This paper presents a new marine exposure site being developed on the North-west Atlantic coastline of Ireland in Co. Donegal by the Centre for Built Environment Research at Queen’s University Belfast. The site will initially contain a number of large precast concrete stems, each 1.5m high, 1.5m wide and 1m thick placed on concrete plinths poured in-situ. The concrete stems will be placed at three levels to achieve different exposure conditions outlined in EN 206, namely atmospheric (XS1), a splash or spray zone (XS3) and a tidal zone (XS3) where the stems will be submerged by the incoming tide twice daily. The concrete will consist of different cements and appropriate w/b ratios suitable for this type of exposure. The permeability and diffusion properties will be measured using non-destructive tests developed at Queen’s University Belfast, namely the Autoclam permeability system and the Permit ion migration test. Other tests to measure the corrosion of the embedded rebar will also be undertaken. In order to monitor the internal concrete properties, electrical sensors will be attached to the rebar and embedded in concrete. The information from these sensors will be relayed back to the office using remote wireless technology. Such integrated monitoring systems for concrete structures can reduce assessment and repair costs by continuously profiling the covercrete and corrosion for the ingress of various deleterious substances, such as chlorides, in the reinforcing steel in real-time. This approach permits an informed assessment of the performance of the structure throughout its service life. This site will form part of a world-wide exposure study, including similar sites in Scotland, India and China.